At CRWA we are working toward a resilient and equitable future for humans and nature. We are designing and promoting infrastructure that will replicate natural systems and integrate management of drinking water, wastewater, and stormwater.

Current Challenges

Traditional urban water infrastructure is having devastating effects on our surface and groundwater resources. Groundwater, which supplies the necessary continuous base flow to the Charles River, is aggressively pumped to provide potable water for cities and towns. It also infiltrates into sewer pipes where energy is wasted pumping and treating it and it is discharged far from its source, permanently lost from the local aquifer. The Charles River and surrounding urban watersheds lose about 90 million gallons a day through sewer infiltration - clean, freshwater that is ultimately discarded into Boston Harbor. Extensive development and impervious cover prevent rainwater from getting into the ground to recharge these lost groundwater sources. Instead, rainwater runs across pavement, picking up pollutants and discharging them to local water bodies. Every year, about 20” of rain that should be infiltrated becomes stormwater runoff. Climate change predictions for our region call for significant increases in large, intense rain events which will lead to increased flooding. In addition, traditional water infrastructure misses the opportunity to recapture the energy and resources in our wastewater.

Our Vision

CRWA envisions a new paradigm in urban infrastructure that integrates water management, mimics natural water, carbon and nutrient cycles and ultimately rejects the concept of “waste”.

Wastewater treatment will take place at decentralized Community Water and Energy Resource Centers(CWERCs). Water will be treated while energy is captured from both the biological components through anaerobic digestion and the physical components through thermal heat capture. Organic food waste will be diverted from landfills to these facilities, reducing trucking and capturing the biogas produced by the degrading organic matter. Solid waste will be transformed into beneficial products such as compost for local food production. Treated water will be reused for non-potable uses such as heating and cooling, manufacturing or irrigation, reducing the demand on potable water sourced from local ground or surface water resources.

Some of the treated water will also restore the natural environment and beautify our neighborhoods through the creation of stream and wetland features and through groundwater infiltration. Green infrastructure fed by treated water will also provide treatment and storage of stormwater, integrating the two systems. Human water use will be merely a bend in the river, fitting into the natural cycle, not destroying it.

Urban Smart Sewering by the Numbers

Charles River Watershed Association has done extensive research and modeling to bring our vision from an idea to a reality. Working with wastewater professionals at Natural Systems Utilities and economists at Industrial Economics we have carefully examined the costs and benefits of Community Water and Energy Resource Centers (CWERCs) and associated green infrastructure districts. This analysis was done for a representative urban neighborhood, roughly 1600 acres in size with 79% impervious cover.

The study found that for every 2 million gallons of wastewater treated, about what 20,000 people generate each day and 4 trucks of food scraps from nearby food producers and restaurants, a CWERC could produce:

1.5 million gallons of treated water per day for flushing toilets, laundry, irrigation and industrial uses which will reduce the demand on drinking water

800 million BTUs of heat per day

7,480 MWh of electricity annually

37 cubic yards of fertilizer per day

The study found that approximately 50 acres of green infrastructure will:

Treat all the stormwater during a 1 inch storm (and the first inch during heavier storms)

Reduce flooding

Increase wildlife habitat

Improve public health

Increase opportunities for recreation

Smart Growth Sewering

Littleton, MA: In 2010, CRWA embarked on a pilot project with the Town of Littleton, MA to explore opportunities for creating a denser, more vibrant village center. Using Smart Sewering strategies, CRWA developed a conceptual design for limited, strategic sewering and local wastewater treatment in which treated water is returned to the ground near where it was originally pumped. This approach allows municipalities to target community growth and development, without creating undesired sprawl. In addition, Smart Sewering restores the natural environment, protects public drinking water supplies and preserves public health.

The Town of Littleton has begun the design process for the Littleton Common Sewer Project. In April 2017, the engineering firm of Weston & Sampson was contracted to create a design for this project.

Wrentham and Sherborn, MA: Since 2012, CRWA has worked with the communities of Wrentham and Sherborn, MA to investigate the use of Smart Sewering in three neighborhoods, including opportunities to use wastewater infrastructure to direct and control growth, recharge depleted aquifers, and replace insufficient septic treatment. With these projects, CRWA has encouraged both communities to consider recapturing resources from wastewater as a means of producing energy, nutrients, non-potable water, and fertilizers.

CRWA worked closely with Town staff and citizen steering committees to develop a suite of technical, economic, legal and regulatory, and zoning tools to support further investigation and implementation of Smart Sewering in both communities. The Wrentham and Sherborn committees will continue working locally within the towns, using the materials provided by CRWA.